Support for the Suspension of a Roller Broom on a Sweeping Vehicle

ABSTRACT

A support system ( 1 ) for the suspension of a roller broom ( 2 ) on a sweeping vehicle comprises a rotary support ( 3 ) mounted to turn on the sweeping vehicle around a vertical slewing axis ( 7 ), a support part ( 5 ) suspended on the rotary support via a lifting mechanism ( 4 ) comprising a lifting drive ( 26 ), and a broom frame ( 6 ) mounted on the support part to rock around a horizontal axis ( 16 ) extending perpendicular to the axis of rotation (L) of the roller broom. For this purpose there is provided, in the region of the pendulum bearing ( 14 ) of the broom frame, a movably mounted locking member ( 17 ), which can occupy a first position that enables the rocking movement of the broom frame and a second position that disables the rocking movement of the broom frame in its leveled condition, and on which the lifting drive of the lifting mechanism acts in such a way that the locking member occupies its second position when the lifting drive is activated.

The present invention relates to a support system for the suspension of a roller broom on a sweeping vehicle, comprising a rotary support mounted to turn on the sweeping vehicle around a vertical slewing axis, a support part suspended on the rotary support via a lifting mechanism comprising a lifting drive, and a broom frame mounted on the support part to rock around a horizontal axis extending perpendicular to the axis of rotation of the roller broom.

Such support systems are known from practice. Sweeping vehicles in which the roller brooms are suspended by means of appropriate support systems are used, for example, for so-called black-clearing at airports, where snow must be removed as completely as possible from traffic surfaces. The pendulum suspension of the roller broom then compensates on the one hand for local fluctuations of the side inclination of the surface to be cleaned, and on the other hand any lateral roll of the sweeping vehicle when cornering, for example. In known support systems of the class in question, the rocking position of the broom frame is urged into a home position by means of suitable spring elements (such as rubber springs or gas-filled springs), in order actively to level the broom unit (meaning the broom frame together with the roller broom suspended thereon), which is raised during transport travel of the sweeping vehicle. Such leveling is important, because the snow burden that otherwise frequently occurs in practice on one side (especially due to snow dust deposited on the broom cover) causes the roller broom to scrape on one side during transport travel. In such sweeping vehicles, in which the roller broom is locked in longitudinal direction of the sweeping vehicle during transport travel, the roller broom would also scrape on one side during acceleration and braking of the sweeping vehicle if such leveling of the broom unit did not take place.

US 2004/0040103 A1 discloses a support system for the suspension of a roller broom on a sweeping vehicle, with the difference from the prior art of the class in question explained hereinabove that no lifting mechanism comprising a lifting drive is provided therein. For lack of an ability to lift the support part, the problem addressed in the foregoing is not solved therein.

From U.S. Pat. No. 4,643,261 A there can be inferred a support system for the suspension of a roller broom on a sweeping vehicle, with the difference from the prior art of the class in question explained hereinabove that the broom frame therein is not mounted on the support part to rock around a horizontal axis extending perpendicular to the axis of rotation of the roller broom. For lack of such rocking ability, the problem addressed in the foregoing is also not solved therein.

In known sweeping vehicles with support systems configured according to the class in question for the roller broom, the result of cleaning is unsatisfactory under various service conditions (such as cornering at a speed above a specified value). The object of the present invention is to remedy this shortcoming.

This object is achieved according to the present invention in that, in a support system of the class in question, there is provided in the region of the pendulum bearing of the broom frame a locking member, which can occupy a first position that enables the rocking movement of the broom frame and a second position that disables the rocking movement of the broom frame in its leveled condition, and on which there acts the lifting drive of the lifting mechanism in such a way that the locking member occupies its second position when the lifting drive is activated. A characteristic viewpoint of the present invention is therefore that the lifting drive of the lifting mechanism acts on the locking member and, when the lifting drive is activated in order to raise the broom unit, the locking member is necessarily actuated, and specifically is brought from its first position enabling rocking movements of the broom frame into its second position disabling the rocking movement of the broom frame in leveled condition. On the way from its first to its second position, this locking member brings the broom frame into its leveled condition. If the lifting drive is nevertheless deactivated during use of the broom (for example by a hydraulic lifting cylinder switched to floating position), so that the roller broom can follow the surface to be cleaned by vertical compensating movements, rocking movements of the roller broom that compensate for different side inclinations of the surface to be cleaned and/or different lateral rolls of the sweeping vehicle are also directly possible. A particular advantage is then that the broom unit can rock freely and without any bias force in the floating position defined by the first position of the locking member. In this way, it is ensured that the roller broom bears over its entire length with the same bearing force on the surface to be cleaned even in the case of substantial lateral roll of the sweeping vehicle, especially while cornering at high speed. This is a decisive difference compared with prior art sweeping machines, in which lateral roll of the sweeping vehicle leads to a different bearing force of the roller broom over its length due to the bias force of the broom frame toward a home position relative to the chassis of the vehicle. Without complex technical devices, therefore, the roller broom is automatically leveled and fixed in this position according to the invention while the broom unit is raised, and is enabled in its lower position, or in other words is decoupled from the chassis of the sweeping vehicle as much as possible.

Although a different mounting of the locking member (especially on the support part or on the broom frame) is entirely conceivable in the scope of the present invention, the locking member according to a first preferred improvement of the invention is mounted to swivel around an axis extending parallel to the axis of rotation of the roller broom, and in fact particularly preferably on the broom frame. In the latter cited case, the point of action of the lifting drive and the articulated linkage of the locking member can be disposed on the broom frame, especially on different sides of the broom frame. Such a configuration is characterized by particularly high functionality.

The same is true if the locking member in its first position comprises part of a stop device to limit the rocking movement of the broom frame to a predetermined range. With such a dual function of the locking member, the inventive support system is effective with a minimum of components. Specifically in this case, it is particularly favorable if shock-absorbing buffer elements that come into effect at least near the end of the permissible rocking movement are disposed on the locking member.

According to another preferred improvement of the invention, it is provided that the locking member is formed as a bracket provided with two cheeks, which bracket embraces the connecting joint between the support part and the broom frame. In this case it is particularly preferable for the support part to be provided adjacent to its articulated connection with the broom frame with respective stops for each of the two cheeks of the bracket.

Certainly the present invention can obviously be implemented with differently constructed lifting mechanisms. According to a particularly preferred improvement of the invention, however, the lifting mechanism comprises a parallelogram-type linkage. It is then particularly favorable if the parallelogram-type linkage comprises two double link arms, wherein the link-arm pairs of the two double link arms respectively receive the support part and the rotary support between them. The lifting drive can also be disposed between the link-arm pairs of the two double link arms in this case, whereby it is mounted in particularly well protected manner. Nevertheless, a corresponding arrangement of the lifting drive between the rotary support and the support part is also advantageous if the parallelogram-type linkage of the lifting mechanism does not comprise any double link arms.

The present invention will be explained in more detail hereinafter on the basis of a preferred practical example illustrated in the drawing, wherein:

FIG. 1 shows a perspective, slightly schematic view, looking obliquely from the left rear upper region, of a support system according to the present invention with the broom unit lowered,

FIG. 2 shows a detail view of the region of the pendulum suspension of the broom frame of the support system according to FIG. 1,

FIG. 3 shows a view, looking obliquely from the left rear upper region, of the support system according to FIGS. 1 and 2 with the broom unit raised, and

FIG. 4 shows a view, looking obliquely from the left front lower region, of the support system according to FIGS. 1 to 3, also with the broom unit raised.

Support system 1 shown in the drawing for the suspension of a roller broom 2 on a sweeping vehicle comprises a rotary support 3, a lifting mechanism 4, a support part 5 and a broom frame 6. Rotary support 3 is mounted on the sweeping vehicle and can turn around a vertical slewing axis 7. Thereto there is linked support part 5, which can be raised and lowered via lifting mechanism 4. For this purpose, the lifting mechanism comprises a parallelogram-type linkage 8 with an upper double link arm 9 and a lower double link arm 10. The link-arm pairs of each of the two double link arms 9 and 10, connected in known articulated manner to rotary support 3 and support part 5, receive support part 5 and rotary support 3 between them. The two link arms 11 of lower double link arm 10 are rigidly connected to one another by means of two connecting pieces 12 and 13.

On support part 5 there is suspended broom frame 6, which is constructed as a rectangular pipe and on which roller broom 2 is mounted to rotate in a manner known in itself around its long axis L. This suspension is achieved by a pendulum bearing 14 in the form of a swivel joint 15, which connects broom frame 6 to support part 5 such that it can rock around horizontal axis 16 extending perpendicular to axis of rotation L of roller broom 2.

In the region of pendulum bearing 14 there is provided a locking member 17 in the form of a bracket 18, which comprises two cheeks 19 and 20, two connecting pieces 21 and 22 connecting these to one another and two stiffening plates 23 and 24. This bracket 18 embraces swivel joint 15, by the fact that the two cheeks 19 and 20 are disposed on different sides of the swivel joint. On front connecting piece 21 there acts, via a ball head, a lifting cylinder 25, which forms lifting drive 26 associated with lifting mechanism 4 and whose other, upper end is stopped against rotary support 3, again via a ball head.

By means of the two bearing straps 27 welded on broom frame 6, bracket 18 is mounted on broom frame 6 such that it can slew around axis 28 extending parallel to axis of rotation L of roller broom 2. Thereby it can occupy a lowered, first position releasing the rocking movement of broom frame 6 and a raised, second position leveling the broom frame and disabling the rocking movement of the leveled broom frame. In the second position of bracket 18, raised by activated lifting cylinder 25, cams 29 of cheeks 19 and 20 bear against the underside of a stop plate 30, which forms a component of support part 5. Hereby the rocking movement of broom frame 6 is locked in its leveled condition; at the beginning of raising of the broom unit as a result of activation of lifting cylinder 25, bracket 18 is brought from its first position into its second position, thus leveling the broom unit. In contrast, bracket 18 can occupy its lowered first position when the hydraulic cylinder is switched into its floating position, in which the broom unit can follow ground irregularities and/or different elastic deflections of the sweeping vehicle without hindrance by corresponding up and down movements of the support part. In this first position of bracket 18, the broom unit can execute rocking movements around swiveling axis 16 without hindrance and without any bias force, within a predetermined angular range.

In order to cushion rocking movements at the end of the permissible range, buffer elements 31 and 32, which are formed as rubber buffers attached at the top and bottom of a corresponding beam 33, are provided on each of cheeks 19 and 20 of bracket 18. When bracket 18 occupies its first position, the two lower buffer elements 32 bear on the top of broom frame 6, and so a small gap permitting elastic deflection of the lower buffer elements 32 is present between cheeks 19, 20 and the top side of broom frame 6; a gap—in the leveled condition of the broom unit—is also present on both sides between cams 29 of cheeks 19 and 20 and stop plate 30. If the broom unit is deflected from its leveled condition, that one of the two upper buffer elements 31 which is located on the upwardly moving side of the broom unit comes into contact, at a predetermined rocking angle, with the underside of stop plate 30, thus damping further rocking movement before or possibly when, during further compression of upper buffer element 31, cam 29 associated with this side strikes against the stop plate. The two lower buffer elements 32 are also compressed in this case, to the point, in fact, that the lower edges of cheeks 19 and 20 bear on the top of broom frame 6. To this extent bracket 18 in its first position also represents part of a stop device limiting the rocking movement of broom frame 6.

Merely for clarification it is pointed out that a gap between upper buffer elements 31 and stop plate 30 is by no means absolutely necessary in the first position of bracket 18. To the contrary, it is entirely possible for the two upper buffer elements 31 to bear against stop plate 30 and for the two lower rubber buffers 32 to bear against broom frame 6 in the first position of bracket 18 with leveled broom unit. Even in this case, the corresponding support system still exhibits a decisive advantage compared with the prior art, because the buffer elements, in contrast to the spring units used in known support systems, can be made to be relatively compliant, depending on how positional stability of the raised broom unit in its leveled condition is achieved by the explained separate locking member.

Obviously the broom unit suspended on the illustrated support system is capable of more than executing rocking movements around swiveling axis 16 without hindrance. Compared with the prior art, up and down movements of the broom unit to follow ground irregularities are also facilitated within a predetermined fluctuation range. This is so because not every deflection movement of the broom unit in vertical direction leads to a change in length of lifting cylinder 25 and thus to displacement of hydraulic fluid to prevent rapid deflection; to the contrary, the broom frame together with support part 5 can execute movements within a predetermined fluctuation range in vertical direction without causing a change in length of lifting cylinder 25, because of the gap of cheeks 19 and 20 of bracket 18 between stop plate 30 on the one hand and broom frame 6 on the other hand. This is particularly favorable for an excellent cleaning result on surfaces with relatively short and shallow ground irregularities. 

1. A support system (1) for the suspension of a roller broom (2) on a sweeping vehicle, comprising a rotary support (3) mounted to turn on the sweeping vehicle around a vertical slewing axis (7), a support part (5) suspended on the rotary support via a lifting mechanism (4) comprising a lifting drive (26), and a broom frame (6) mounted on the support part to rock around a horizontal axis (16) extending perpendicular to the axis of rotation (L) of the roller broom, characterized in that there is provided, in the region of the pendulum bearing (14) of the broom frame, a movably mounted locking member (17), which can occupy a first position that enables the rocking movement of the broom frame and a second position that disables the rocking movement of the broom frame in its leveled condition, and on which there acts the lifting drive of the lifting mechanism in such a way that the locking member occupies its second position when the lifting drive is activated.
 2. A support system according to claim 1, characterized in that the locking member (17) is mounted to swivel around an axis (28) extending parallel to the axis of rotation (L) of the roller broom (2).
 3. A support system according to claim 1, characterized in that the locking member (17) is mounted in articulated manner on the broom frame (6).
 4. A support system according to claim 3, characterized in that the point of action of the lifting drive (26) and the bearing of the locking member (17) are disposed on the broom frame (6), on different sides of the broom frame.
 5. A support system according to claim 1, characterized in that the locking member (17) is formed as a bracket (18) provided with two cheeks (19, 20), which bracket embraces the pendulum bearing (14) between the support part (5) and the broom frame (6).
 6. A support system according to claim 5, characterized in that the support part (5) is provided adjacent to the pendulum bearing (14) with respective stops for each of the two cheeks (19, 20) of the bracket (18).
 7. A support system according to claim 1, characterized in that the locking member (17) in its first position represents part of a stop device limiting the rocking movement of the broom frame (6).
 8. A support system according to claim 7, characterized in that shock-absorbing buffer elements (31, 32) are disposed on the locking member (17).
 9. A support system according to claim 1, characterized in that the lifting mechanism (4) comprises a parallelogram-type linkage (8).
 10. A support system according to claim 9, characterized in that the parallelogram-type linkage (8) comprises two double link arms (9, 10), wherein the link-arm pairs of the two double link arms respectively receive the support part (5) and the rotary support (3) between them.
 11. A support system according to claim 1, characterized in that the lifting drive (26) is disposed between the rotary support (3) and the support part (5). 